Treffer: RELIABLE AND EFFICIENT FIBER OPTICAL CABLE ORIENTATION MAPPING TECHNOLOGY BEHIND CASING USING FIBER LOCATING TOOLS IN CHANGQING OILFIELD.

The staged fracturing technology of horizontal wells has become the most effective method for the development of low-permeability tight oil sandstone reservoirs. The distributed optical fiber sensing technology provided by the optical cable deployed outside the casing is expected to help operators better understand the parameters of fracturing reconstruction and increase productivity. In this paper, a technology that uses a more effective optical fiber positioning tool to identify the position of the optical cable outside the sleeve is introduced. In order to eliminate the complexity of fiber deployment, the fiber positioning signal transmitter unit is used to deploy the fiber optic cable outside the casing. The tool uses sensors, sound transducers and electronic components to measure and calculate the position of the downhole fiber optic cable, and then these information modulations are acoustically transmitted to the ground. The acoustic signal picked up by the optical cable connected to the distributed acoustic sensor system on the ground is used to obtain the measurement data of the downhole sensor. Once the position of the tool is known, the position of the fiber optic cable can be calculated and then used to calculate a safe position to guide the perforation angle. In this study, the target horizontal well has a total length of 3,256 meters, a horizontal section of 1,327 meters, and a bottom hole temperature of55-60°C. It has carried out technical services for the positioning of the pre-installed optical fiber outside the casing. 29 optical fiber positioning signal transmission units are deployed along the optical cable outside the casing, and the DAS technology is used to locate the preinstalled optical cable outside the casing. Moreover, the position information of 29 signal transmitting units was obtained as a result of optical fiber positioning signal data analysis. After entering the well, all 29 signal transmitting units were in normal working condition. The signal transmitting unit 29-21 and the signal transmitting unit 20-01, from a front perspective, the optical cable appears to be wound counterclockwise outside the sleeve. In addition, the angles of the 21st and 20th signal transmitting units have changed greatly, which caused the casing to rotate during the fiber optic cable entering the well, which caused the downhole fiber optic cable to undergo a large azimuth change. The test result is consistent with the actual situation on site. Therefore, this new method does not require additional cable entry operations to determine the position of the fiber optic cable, and can provide a higher-precision fiber optic cable positioning result immediately after the casing is deployed. [ABSTRACT FROM AUTHOR]

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